[Surgical application of low-power laser: experimental study, development of equipments and clinical application]

We carried out experimental and clinical studies with low-power laser to perform the surgical application. The developed device for microvascular anastomosis with semiconductor laser diode made of In-Ga-As-P was used to perform 15 end-to-end laser assisted microvascular anastomoses of carotid arteries in rabbits. In four of 7 cases which were irradiated with power output 50mW showed patency immediately after surgery with no wound disruption. A new medical device with Ga-A1-As semiconductor laser diode was developed for pain relief. A double-blind evaluation of the test was initiated in 124 patients suffering from chronic inflammatory pain. Result is that of 63 patients irradiated laser, 45(71%) were effective and of 61 cases not irradiated laser, 8(13%) were relieved pain. The data were analyzed statistically by chi square, and criterion for statistical significance was the 0.01 level. The spectral properties of laser-excited fluorescence of three photosensitizers, namely tetracycline, hematoporphyrin free base and chlorin e6Na, taken up in human arterial intima were detected. Photosensitizers were administrated to resected human arteries for 2 hours in vitro. The main results are following: 1) Photosensitizers are confirmed to be taken up in arterial intima and the fluorescence intensity decreases as the time goes on. 2) The fluorescence intensity from atheromatous plaque is usually stronger than that from normal region.